Scroll compressor

ABSTRACT

A scroll compressor includes a body container that is a hermetically sealed container; a fixed scroll that is fixed to an upper portion of an inside of the body container; an orbiting scroll that is disposed below the fixed scroll; a rotary drive shaft including an oil passing hole that connects an upper side and a lower side in the shaft; a frame that is fixed to an inner peripheral surface of the body container to slidably support the orbiting scroll; a thrust plate that is disposed between a lower surface of the orbiting scroll and a thrust support surface of the frame; an Oldham ring that is accommodated in the frame; and an orbiting-side Oldham groove that guides the Oldham ring, wherein a circumferential groove that communicates with the orbiting-side Oldham groove is formed in the lower surface of the orbiting scroll.

CROSS REFERENCE TO RELATED APPLICATION

This application is a U.S. national stage application ofPCT/JP2014/002017 filed on Apr. 9, 2014, the contents of which areincorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a scroll compressor that is primarilymounted on a refrigerant circuit of a refrigerator, an air-conditioningapparatus, a water heater, or other devices.

BACKGROUND

As an existing scroll compressor, a scroll compressor in which, when thematerial of an orbiting scroll is cast iron, the orbiting scroll, abimetal thrust bearing that supports the orbiting scroll, and a thrustplate made of Swedish steel are slid to form a thrust bearing is known.

Alternatively, a scroll compressor in which, when a thrust load is largeor when sliding characteristics are not adequate, wear and seizurebetween an orbiting scroll and a thrust bearing are prevented byproviding an oil supply hole that extends from a boss section of theorbiting scroll to a thrust surface of the orbiting scroll andincreasing an oil supply amount is known (refer to, for example, PatentLiterature 1).

Still alternatively, a scroll compressor that increases wear resistanceof a thrust bearing section by, at a thrust bearing surface thatsupports an orbiting scroll, forming a plurality of spiral groovemechanisms or a plurality of taper land bearing mechanisms andgenerating oil film pressure is known (refer to, for example, PatentLiterature 2).

PATENT LITERATURE

Patent Literature 1: Japanese Unexamined Patent Application PublicationNo. 5-149277 (paragraphs [0011] to [0016], FIG. 1)

Patent Literature 2: Japanese Unexamined Patent Application PublicationNo. 8-319959 (paragraphs [0018] to [0039], FIGS. 1 to 3)

An existing thrust bearing structure is a simple structure in which theorbiting scroll made of cast iron and the thrust plate made of Swedishsteel or other materials are slid. Since a bimetal thrust bearing is notused, under a condition in which a thrust load is increased, slidabilitybetween the orbiting scroll and the thrust plate deteriorates, as aresult of which a back surface (lower surface) of the orbiting scroll issubjected to, for example, wear and seizure.

SUMMARY

The invention is made to solve the above-described problems. It is anobject of the invention to provide a scroll compressor that can suppresswear and seizure of a lower surface of an orbiting scroll even if thescroll compressor has a simple structure that does not use an expensivebimetal thrust bearing.

A scroll compressor according to an embodiment of the invention includesa body container that is a hermetically sealed container; a fixed scrollthat is fixed to an upper portion of an inside of the body container; anorbiting scroll that is disposed below the fixed scroll and that,together with the fixed scroll, forms a compression chamber, theorbiting scroll including a boss section at a central portion of a lowersurface of the orbiting scroll; a rotary drive shaft having an eccentricshaft section formed at an upper end portion of the rotary drive shaft,the rotary drive shaft including an oil passing hole that connects anupper side and a lower side in an inside of the shaft, the eccentricshaft section being rotatably supported by an orbiting bearing at theboss section of the orbiting scroll; a frame including a thrust supportsurface that receives the orbiting scroll, a recessed section that isformed inwardly from the thrust support surface in a radial direction ofthe body container and that accommodates the boss section of theorbiting scroll, and a main bearing section that is formed at a lowerportion of the recessed section and that rotatably supports the rotarydrive shaft, the frame being fixed to an inner peripheral surface of thebody container; a thrust plate that is disposed between the lowersurface of the orbiting scroll and the thrust support surface of theframe and that slidably supports the lower surface of the orbitingscroll; an Oldham ring that is accommodated the frame and that restrictsrotation of the orbiting scroll around an axis of the rotary driveshaft; and an orbiting-side Oldham groove that is formed in the lowersurface of the orbiting scroll outwardly from the boss section, theorbiting-side Oldham groove accommodating a part of the Oldham ring,wherein a circumferential groove that communicates with theorbiting-side Oldham groove is formed in the lower surface of theorbiting scroll.

In the scroll compressor of an embodiment of the invention, since thecircumferential groove that communicates with the orbiting-side Oldhamgroove is formed in the lower surface of the orbiting scroll, it ispossible to supply a sufficient amount of lubricating oil between theorbiting scroll and the thrust plate, and to generate oil film pressureby the wedge effect. As a result, the advantageous effects of preventingwear and suppressing seizure at the lower surface of the orbiting scrollare obtained.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a vertical sectional view of a scroll compressor in Embodiment1 of the invention.

FIG. 2 illustrates an orbiting scroll of the scroll compressor, withFIG. 2(a) being a sectional view taken in the direction of the arrowsalong line A-A of FIG. 2(b), and FIG. 2(b) being a bottom view.

FIG. 3 illustrates a frame of the scroll compressor, with FIG. 3(a)being a plan view and FIG. 3(b) being a sectional view taken in thedirection of the arrows along line B-B of FIG. 3(a).

FIG. 4 is a plan view showing a state in which an Oldham ring is mountedin the frame of the scroll compressor.

FIG. 5 is a vertical sectional view of an orbiting scroll and a frame ofa scroll compressor in Embodiment 2 of the invention.

DETAILED DESCRIPTION Embodiment 1

In Embodiment 1, wear and seizure of a thrust surface of an orbitingscroll are suppressed.

FIG. 1 is a vertical sectional view of a scroll compressor in Embodiment1 of the present invention. FIG. 2 illustrates an orbiting scroll of thescroll compressor. FIG. 3 illustrates a frame of the scroll compressor.FIG. 4 is a plan view showing a state in which an Oldham ring is mountedin the frame of the scroll compressor.

In each figure, the scroll compressor according to Embodiment 1 sucksrefrigerant that circulates through a refrigerant circuit, compressesthe refrigerant to a state of high temperature and high pressure, anddischarges the refrigerant to the refrigerant circuit. The scrollcompressor includes a body container 100 that is a hermetically sealedcontainer; a fixed scroll 101 that is fixed to and disposed at an upperportion of the inside of the body container 100; an orbiting scroll 102that is disposed below the fixed scroll 101 and that includes a bosssection 102 c at a lower surface thereof; a rotary drive shaft 114including an oil passing hole 114 a that connects an upper side and alower side in the shaft; a frame 105 that is fixed to and disposed at acontainer inner peripheral surface of an intermediate portion of thebody container 100; a thrust plate 104 that slidably supports theorbiting scroll 102 and that has the form of a ring plate; and an oilpump 108 that is connected to a lower portion of the rotary drive shaft114. A discharge pipe 113 for discharging refrigerant gas is connectedto an upper portion of the body container 100, and a suction pipe 112for sucking the refrigerant gas is connected to a body section of thebody container 100. The oil pump 108 pumps up lubricating oil(refrigerating machine oil) 109 that accumulates at a bottom portion ofthe body container 100, and sends the lubricating oil to the oil passinghole 114 a.

The frame 105 includes a thrust support surface 105 c that supports theorbiting scroll 102, a recessed section 105 b that is formed inwardlyfrom the thrust support surface 105 c in a radial direction of thecontainer and that is used for accommodating the boss section 102 c ofthe orbiting scroll 102, and a main bearing section 105 a that is formedat a lower portion of the inside of the recessed section 105 b and thatrotatably supports the rotary drive shaft 114. An eccentric shaftsection 110 that is rotatably supported by an orbiting bearing 102 a atthe boss section 102 c of the orbiting scroll 102 is formed at an upperend portion of the rotary drive shaft 114. An Oldham ring 103 thatrestricts rotation of the orbiting scroll 102 around an axis C of therotary drive shaft 114 is accommodated in the recessed section 105 b ofthe frame 105. A frame-side Oldham groove 105 d for guiding the Oldhamring 103 is formed in the recessed section 105 b of the frame 105, withthe frame-side Oldham groove 105 d being long in the radial direction(refer to FIGS. 3 and 4).

The thrust plate 104 that is made of a steel-plate-based material andthat slidably supports the orbiting scroll 102 is disposed between athrust surface 102 e at the lower surface of the scroll 102 and thethrust support surface 105 c of the frame 105. A cutaway portion 104 bthat communicates with the frame-side Oldham groove 105 d is formed inthe thrust plate 104 at a location thereof that faces the frame-sideOldham groove 105 d. The cutaway portion 104 b is formed with a shapehaving a size that is slightly larger than that of the frame-side Oldhamgroove 105 d. A thrust bearing section is formed by bringing theorbiting scroll 102 and the thrust plate 104 in close contact with eachother via the lubricating oil 109. The thrust plate 104 has a functionof adjusting a gap in a compression chamber 111 in the direction of theaxis C of the rotary drive shaft.

A lap 101 a that is provided vertically on a lower surface (backsurface) of a base plate is formed at the fixed scroll 101. A lap 102 bthat is provided vertically on an upper surface of a base plate and thathas substantially the same shape as the lap 101 a is formed at theorbiting scroll 102. The orbiting scroll 102 and the fixed scroll 101are made of a cast-iron-based material, and are mounted in the bodycontainer 100 with the lap 102 b and the lap 101 a combined with eachother. With the orbiting scroll 102 and the fixed scroll 101 combinedwith each other, a spiral direction of the lap 101 a and a spiraldirection of the lap 102 b are opposite each other. The compressionchamber 111 whose volume changes relatively is formed between the lap 10a and the lap 9 a.

The fixed scroll 101 is fixed to an opening-port edge portion at anupper surface of the frame 105 with, for example, a bolt (not shown). Onthe other hand, the boss section 102 c having a hollow cylindrical shapeextends downward from a substantially central portion of the lowersurface of the orbiting scroll 102, and an inner peripheral surface ofthe boss section 102 c corresponds to the orbiting bearing 102 a. Anorbiting-side Oldham groove 102 d that guides an upper protrusion 103 aof the Oldham ring 103 is formed at a location in the lower surface ofthe orbiting scroll 102 that is situated outwardly from the boss section102 c, with the orbiting-side Oldham groove 102 d being long in theradial direction (refer to FIG. 2). By the Oldham ring 103 forpreventing rotation movement, the orbiting scroll 102 revolves(so-called orbital movement) without rotating with respect to the fixedscroll 101.

The eccentric shaft section 110 that is provided at an upper end of therotary drive shaft 114 is rotatably placed into the orbiting bearing 102a. By causing an inner peripheral portion of the orbiting bearing 102 aand an outer peripheral portion of the eccentric shaft section 110 toslidably closely contact each other via the lubricating oil 109, anorbiting bearing section is formed. An electric motor 115 includes arotor 106 and a stator 107, the rotor 106 being fixed to the rotarydrive shaft 114 and the stator 107 being fixed to the container innerperipheral surface of the intermediate portion. By starting energizationto the stator 107, the rotor 106 is rotated and driven to rotate therotary drive shaft 114.

The rotary drive shaft 114 rotates as the rotor 106 rotates, and rotatesthe orbiting scroll 102. An upper portion of the rotary drive shaft 114(location near the eccentric shaft section 10) is supported by the mainbearing section 105 a of the frame 105. A ball bearing 117 is mounted ona central portion of a sub-frame 116 fixed to an inner peripheralsurface of a lower portion of the body container 100, and rotatablysupports the lower portion of the rotary drive shaft 114. The oil pump108 of a displacement type is mounted on the sub-frame 116. The oil pump108 is connected to the rotary drive shaft 4, and is subjected to rotaryforce. The lubricating oil 109 sucked by the oil pump 108 is sent toeach sliding section via, for example, the oil passing hole 114 a of therotary drive shaft 114.

Next, an operation is described.

In the scroll compressor having such a structure, when voltage isapplied to the electric motor 115, the rotary drive shaft 114 is rotatedand driven, and the eccentric shaft section 110 rotates in the orbitingbearing 102 a. Then, the orbiting scroll 102 whose rotation issuppressed by the Oldham ring 103 undergoes orbital movement. Thiscauses part of refrigerant gas to flow into the compression chamber 111via a suction port of the frame 105, and a suction process is started.The remaining part of the refrigerant gas passes through a cutawayportion of the stator 106, and cools the electric motor 115 and thelubricating oil 109.

The orbital movement of the orbiting scroll 102 causes the compressionchamber 111 to gradually move toward the center of the orbiting scroll102, and its volume is further reduced. This process causes therefrigerant gas sucked into the compression chamber 111 to becompressed. At this time, the compressed refrigerant gas causes a loadacting in a direction away from the fixed scroll 101 in the direction ofaxis C to act upon the orbiting scroll 102. However, this load isreceived by an upper surface 104 a of the thrust plate 104. Thecompressed refrigerant passes through a discharge port of the fixedscroll 101 and through a discharge pipe 25, and is discharged to therefrigerant circuit from the body container 100. The lubricating oil 109sucked up to the eccentric shaft section 110 by the oil pump 108lubricates the sliding section of a bearing metal of the orbiting scroll102 and the sliding section between the thrust surface 102 e of theorbiting scroll 102 and the upper surface 104 a of the thrust plate 104.Thereafter, part of the lubricating oil 109 flows upstream from an outerperipheral edge of the orbiting scroll 102, and flows into thecompression chamber 111, lubricates the sliding section between the lap101 a and the lap 102 b. The remaining part of the lubricating oil 109flows downward from the inside of the frame 105, and returns to an oilsump at the bottom portion of the body container 100.

In the scroll compressor having the above-described structure, thelubricating oil 109 flows to a circumferential groove 102 f from theorbiting scroll Oldham groove 102 d each time the orbiting scroll 102reciprocates along the orbiting-side Oldham groove 102 d, and asufficient amount of lubricating oil 109 is supplied to the thrustsurface 102 e from the circumferential groove 102 f. Since the thrustplate 104 includes the cutaway portion 104 b, a flow passage forsupplying the lubricating oil 109 from the frame-side Oldham groove 105d to the thrust surface 102 e each time the Oldham ring 103 reciprocatesalong the frame-side Oldham groove 105 d is provided. In the relatedart, since the cutaway portion 104 b described above is not formed inthe thrust plate, the supply of lubricating oil from the frame-sideOldham groove to the thrust surface is hindered.

As described above, according to the scroll compressor of Embodiment 1,it is possible to increase the amount of lubricating oil 109 supplied tothe thrust surface 102 e, so that the wedge effect occurring due to thisincrease makes it possible to generate high oil film pressure. As aresult, it is possible to suppress wear and seizure of the thrustsurface 102 e of the orbiting scroll 102.

Embodiment 2

Although, in Embodiment 1, the lower surface of the orbiting scroll is ahorizontal surface without being inclined, the scroll compressor of thepresent invention is not limited thereto. For example, Embodiment 2 inwhich, as shown in FIG. 5, a thrust surface 102 g of an orbiting scroll102A that is supported by an upper surface 104 a of a thrust plate 104is an inclined surface that extends downward and outward in a radialdirection is also included in the present invention.

According to the orbiting scroll 102A including the inclined thrustsurface 102 g as described above, since a large wedge effect isprovided, it is possible to generate higher oil film pressure. Thismakes it possible to reliably prevent wear and seizure of the thrustsurface 102 e of the orbiting scroll 102.

1. A scroll compressor comprising: a body container being a hermeticallysealed container; a fixed scroll fixed to an upper portion of an insideof the body container; an orbiting scroll disposed below the fixedscroll and, together with the fixed scroll, forming a compressionchamber, the orbiting scroll including a boss section at a centralportion of a lower surface of the orbiting scroll; a rotary drive shafthaving an eccentric shaft section formed at an upper end portion of therotary drive shaft, the rotary drive shaft including an oil passing holeconnecting an upper side and a lower side in the shaft, the eccentricshaft section being rotatably supported by an orbiting bearing at theboss section of the orbiting scroll; a frame including a thrust supportsurface on which the orbiting scroll is placed, a recessed sectionformed inwardly from the thrust support surface in a radial direction ofthe body container and accommodating the boss section of the orbitingscroll, and a main bearing section formed at a lower portion of therecessed section and rotatably supporting the rotary drive shaft, theframe being fixed to an inner peripheral surface of the body container;a thrust plate disposed between the lower surface of the orbiting scrolland the thrust support surface of the frame and that slidably supportsthe lower surface of the orbiting scroll; an Oldham ring accommodated inthe frame and restricting rotation of the orbiting scroll around an axisof the rotary drive shaft; and an orbiting-side Oldham groove formed inthe lower surface of the orbiting scroll outwardly from the bosssection, the orbiting-side Oldham groove accommodating a part of theOldham ring, wherein a circumferential groove that communicates with theorbiting-side Oldham groove is formed in the lower surface of theorbiting scroll.
 2. The scroll compressor of claim 1, wherein a thrustsurface of the orbiting scroll that is supported by an upper surface ofthe thrust plate is an inclined surface that extends downward andoutward in the radial direction.
 3. The scroll compressor of claim 1,wherein a frame-side Oldham groove that guides the Oldham ring is formedin the frame, and a cutaway portion that communicates with theframe-side Oldham groove is formed in the thrust plate at a locationthereof that faces the frame-side Oldham groove.
 4. The scrollcompressor of claim 1, wherein the rotary drive shaft is verticallyextended.
 5. The scroll compressor of claim 1, wherein at least aportion of lubricating oil sucked up to the eccentric shaft sectionthrough the rotary drive shaft and the oil passing hole flows to thecircumferential groove through the orbiting-side Oldham groove.
 6. Ascroll compressor comprising: a rotary drive shaft including an oilpassing hole through which lubricating oil flows; an orbiting scrollattached to the rotary drive shaft, the orbiting scroll having anorbiting-side Oldham groove formed in a lower surface thereof; a frameincluding a thrust support surface on which the orbiting scroll isplaced; a thrust plate disposed between the lower surface of theorbiting scroll and the thrust support surface of the frame; wherein acircumferential groove that communicates with the orbiting-side Oldhamgroove and supplies lubricating oil to a sliding section between theorbiting scroll and the thrust plate is formed in the lower surface ofthe orbiting scroll.